Manufacturing welded articles



Ma 1936- A. KOLLHOF MANUFACTURING WELDED ARTICLES Filed July 11, 1953 INT/ENTER AANULD KULLHUF [Yrs '7 TURNEY Patented Mar. 3, 1936 UNITED STATES MANUFACTURING WELDED ARTICLES) Arnold Kollhof, Spandau-West, Germany, as-

signor to General ElectrieCompany, a corporation of New York Application July 11, 1933, Serial no. 379,958

In Germany 1 Claim.

My invention relates to methods and apparatus for manufacturing welded articles and more particularly to methods and apparatus for welding bayonet pins to bases for electric lamps and similar devices.

The bayonet pins in electric lamps and similar devices have heretofore been attached to the metal base shell by upsetting the ends thereof. This practice has been unsatisfactory due to the fact that the pins were often not rigidly attached and became loosened in use. According to my invention these disadvantages are obviated by providing a method and apparatus for welding the pins to the base shell. The said apparatus comprises a block-shaped electrode having a concave seat therein in which the base shell is supported. A second stud-shaped electrode is provided on a movable arm and is inserted in said base shell. The block-shaped electrode has an insert of highly refractory metal having a hole therein in which the pin is inserted through a hole in the base shell. The second electrode also preferably carries an insert which has a concave surface which forms a rivet head on the pin when it is brought in contact therewith. During the heating of the rivet the shank portion is compressed by the said second electrode so as to fill up the hole in the insert. The size of the pins is thus accurately controlled and fixed by the said hole in said insert, which is an important factor in the proper insertion of lamps having such pins on their bases. Further features and advantages of my invention will appear from the following detailed description thereof. j

In the drawing, Fig. 1 is an elevation of apparatus comprising my invention; Fig. 2 is a detailed elevation in section, and to a larger scale, of the welding electrodes; and Fig. 3 is a front view thereof.

Referring to the drawing, the apparatus'comprises a frame or bed I0 having a pair of guide rails II, I2 between which is mounted a horizontally reciprocating block-shaped welding elec-i trode I3. The electrode I3, which is preferably made of copper, has a. semi-circular seat I4 therein in which a cylindrical base shell I5 is placed. A conical insert I6 of refractory metal such as tungsten or molybdenum is located in the electrode I3 with the top thereof flush with the bottom of the seat portion I4. A hole I! is provided in the electrode I3 under the insert I6 to allow easy removal thereof. Ahole I8 is provided in the insert It to receive a pin I9 which projects through a hole 20 in the base shell I5.

A stud-shaped electrode 2| is disposed above the electrode I3 and enters the shell 15 during the welding operation. Said electrode 2| is mounted on an arm 22 which is plvotally mounted on a pin 23 in a block 24 on the bed III. A verti- August 5, 1932 cally reciprocating arm 25 is mounted on a pin 26 in the end of the arm 22 so that electrode2| may be moved up and down with respect to elec-. trode I3. A conical insert 21 is mounted in the electrode 2| in vertical alignment with insert I6 and has a concave surface 28 which forms a head on the pin IS. A contact arm 29 is provided on the arm 25 and carries a contact plate 30 which is resiliently supported by a spring 3| surrounding a pin portion 32 mounted in the end of said arm 29. Said plate 30 engages a pair of contacts 33, 34 on an arm 35 on the bed I0. Contact 33 is connected to a line 36 which extends to a source of electrical energy, while contact 34 is connected to a line 3'! which extends to one end of a primary coil 38 of a transformer, the other end of which is connected to a line 39. The secondary coil 40 of said transformer is connected to the arm 22 and the electrode I3 by lines 4|, 42 respectively. The forward motion of electrode I3 is arrested by a stop 43 when the inserts I6, 21 are in'vertical alignment.

In operation, the electrode I3 is moved back, or to the right in Fig. 1, a pin I9 is placed in the hole I8 in insert I6, and a base shell I5 is placed over pin IS in the seat portion I4. The electrode I3 is then moved forward to the stop 43. The arm 25 is now moved upward so that contact plate 30 engages contacts 33, 34 and the concave portion 28 of insert 21 in electrode 2| engages the top of pin I9, thereby closing the welding circuit. The pin I9 is heated to plasticity so that the shank portion thereof fills up the hole I8 in insert I6 and the top portion thereof is formed into a head 44 and welded firmly to the base shell I5. The pin ISwill not be welded to the refractory inserts I6, 21 during the brief duration of the operation which takes only a few seconds. The arm 25 is then moveddownward, thus lifting the electrode 2| up, and electrode I3 is moved to the right and the second pin welded in the same manner.

Instead of reciprocating the elctrode I3, it is of course possible to arrange electrode 2| so that it reciprocates into and out of the shell I 5.

What I claim as new and desire to secure by Letters Patent of the United States, is:

The method of uniting a bayonet pin to a metal base shell which consists in assembling said shell and an electrode with an aperture in said shell in line with a recess of definite size in said electrode and with a pin passing through said aperture and extending into said recess, then causing another electrode to engage the inner end of said pin and supplying electrical energy to fuse the said end and to weld the head thus formed to the inner surface of said shell and expand the shank portion of said pin into said recess in said firstmentioned electrode. fl

ARNOLD KOLLHOF. 

